When you're talking to a girl at the bar and your friend comes up to hit on her. To be properly executed, the friend must not understand that he could talk to any other girl in the place, or how shady it is that he only waits for you to break the ice for him without asking.

"Tim didn't give me a heads up that he wanted to talk to this girl, so I assumed if I talked to her I wouldn't get interrupted by him. At the very least he could just ask me to break the ice if he's shy, instead of pulling the sneaky snake."